Add memoization addition and fibonacci examples

Signed-off-by: Darko Draskovic <[email protected]>

src/dynamic/memoization.js

@@ -0,0 +1,82 @@
+function addTo80(n) {
+ console.log('addTo80 takes long time');
+ return n + 80;
+}
+
+function memoizedAddTo80() {
+ let cache = {
+ 7: 87
+ }
+ return function (n) {
+ if (n in cache) {
+ console.log(n, '+ 80 found in cache');
+ return cache[n];
+ }
+
+ console.log('caching', n, '+ 80');
+ cache[n] = n + 80;
+ return cache[n];
+ }
+}
+
+function fibonacci(n) {
+ let numbers = [1, 2];
+ while (n > 2) {
+ numbers.push(numbers[numbers.length - 2] + numbers[numbers.length - 1]);
+ n--;
+ }
+ return numbers;
+}
+
+function memoizedFibonacci() {
+ let numbers = [1, 2];
+
+ return function (n) {
+ let length = numbers.length;
+ let upper = n;
+ while (n > length) {
+ numbers.push(numbers[numbers.length - 2] + numbers[numbers.length - 1]);
+ n--;
+ }
+ return numbers.slice(0, upper);
+ }
+}
+
+var timer = function (name) {
+ var start = new Date();
+ return {
+ stop: function () {
+ var end = new Date();
+ var time = end.getTime() - start.getTime();
+ console.log('Timer:', name, 'finished in', time, 'ms');
+ }
+ }
+};
+
+(function () {
+ // console.log(addTo80(5));
+ // const fn = memoizedAddTo80();
+
+ // console.log(fn(7));
+
+ // console.log(fn(5));
+ // console.log(fn(5));
+ // console.log(fn(5));
+
+ let n = 10e6;
+
+ var t = timer('non memoized fibonacci 1');
+ fibonacci(n);
+ t.stop();
+ var t = timer('non memoized fibonacci 2');
+ fibonacci(n);
+ t.stop();
+
+ const memoFib = memoizedFibonacci();
+ var t = timer('memoized fibonacci 1');
+ memoFib(n);
+ t.stop()
+ var t = timer('memoized fibonacci 2');
+ memoFib(n);
+ t.stop()
+})()